A 52-Year-Old Man with Proximal Limb Weakness and Hand Stiffness

Myotonic dystrophy is the most common muscular dystrophy seen in adults. It is an autosomal dominant disease. It is a unique muscular dystrophy characterized by multisystem involvement, clinical and EMG myotonia, RNA toxicity as the disease-causing mechanism, and lack of dystrophic changes on muscle biopsy. It has two types: myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2). Here we present a patient with DM2, whose initial clinical presentation is mild and non-specific. The DM2 diagnosis was suspected based on the muscle biopsy findings and confirmed by the gene test.